Paper 1. Injection Molding – Due Date: April 15, 1999

Each student will be responsible for completing a technical paper on setting up a pilot production line for injection molding.

You are a plastics manufacturing engineer writing a production proposal to management. You want to give your bosses an estimate on what it would take to make money by producing flying disks. You want to buy a new injection molder so that you can make flying disks. You’d like to sell between 100,000 and 200,000 flying disks per year.

Paper objective: What would be the production manufacturing plan for a flying disk made out of LDPE.

• Part name flying disk.
• Plastic Material: LDPE
• Machine: 200 ton HPM Machine
• Required clamp force: 50 ton (US)
• Required shot size: 6 oz
• Max injection rate: 10 in³/s
• Single cavity part weight: 3.91 oz
• Average part thickness: 0.08 in
• Single cavity projected area: 20 in²
• Fill time: 1 sec
• Cooling time: 10 sec
• Machine open close: 10 sec
• Demold time: 2 sec
• Injection pressure: 6030.53 psi
• Melt temperature: 428.00 F
• Mold temperature:68.00 F
• No secondary operations

• LDPE Material Cost: $0.45 per pound
• Tooling Cost:
• $50,000 for Single Cavity
• $75,000 for Dual Cavity
• Injection Molding Machine Cost: $200,000
• Installation and other machine related Costs are 15% of Purchase Price
• Operators cost: $ 15 per hour plus 30% benefits
• Utilities Cost: Use defaults
• Amortize Tooling costs in one year
• Other costs: Overhead 30%, Profit 10%, Shipping 5%,

• Compare costs for 5,000 parts, 10,000 parts, 50,000 parts, and 100,000 parts. (You choose when to use dual cavity and when to use single cavity)
• Production Rate: 3 shifts for 48 weeks a year.

Introduction (1 page)

[Define the problem. Give background information on your company. You pick the size, location, history in injection molding, and name of your company. Describe your competitors in this area if any. Define opportunity to make money with this part.]

Project Proposal (3 to 4 pages)

[Define the project in to justify the flying disk production including the following sections.]

1. Design information for the part. Include the manufacturing technical input data from above. Use information from lecture on injection molded parts and flow analysis. Flow analysis information for this part will be available in folder in 438.
2. Materials information describing resin mechanical and physical properties, polymer chemistry, suppliers, and cost.
3. Processing information for the part. Include the manufacturing technical input data from above, information from lectures, picture of a machine, describe cycle time, tooling costs, single versus multicavity tools, runners, gates, processing parameters for LDPE, operators needed, automation if any, etc.
4. Plant layout information. Describe how the plant should make the flying disks, i.e., what is the layout of machine, Machine type and location, storage for resin materials, tooling, molded parts, scrap, supplies, equipment, recommended manufacturing plan to achieve rates.
5. Cost information. Include spreadsheet analysis for the flying disk part and compare selling price for annual volumes of 5,000 parts, 10,000 parts, 50,000 parts, and 100,000 parts. (You choose when to use dual cavity and when to use single cavity)

Conclusions and Recommendations

[Describe why your company should spend the $260K to buy and install a new machine and make and sell flying disks. Describe other types of parts that you can make with this. Describe the future for injection molding and flying disks.]